import type { DatabaseClient } from "./database";
import {
  effectiveProjectMembers,
  ensureProjectMainChat,
  findOrCreateGroupOwnerPartner,
} from "./project-service";
import {
  createAppChat,
  getAppChat,
  hasAppCredentials,
  sanitizeChatid,
  sendAppChatMessage,
  updateAppChat,
  type WecomConfig,
} from "./wecom-client";

type FetchLike = typeof fetch;

export type TaskChatEnsureResult = {
  chatId: string | null;
  created: boolean;
  reason?: "no_task" | "no_owner" | "not_enough_members" | "no_credentials";
};

type TaskChatRow = {
  id: string;
  name: string;
  task_chat_id: string | null;
  task_owner_userid: string | null;
  project_owner_userid: string | null;
};

function text(value: unknown) {
  return String(value ?? "").trim();
}

export function taskChatId(taskId: string) {
  return `tgc${sanitizeChatid(text(taskId))}`;
}

function chatNameForTask(taskName: string) {
  return `【任务】${text(taskName)}`.slice(0, 20);
}

async function syncMembers(
  config: WecomConfig,
  chatid: string,
  members: string[],
  fetchImpl: FetchLike,
) {
  const info = await getAppChat(config, chatid, fetchImpl);
  if (!info) {
    // appchat/get 要求应用可见范围为根部门，查不到时降级为只增同步（重复添加成员企微按成功处理）
    await updateAppChat(config, { chatid, addUserList: members }, fetchImpl);
    return;
  }
  const existing = new Set(info.userlist);
  const missing = members.filter((userid) => !existing.has(userid));
  if (missing.length > 0) {
    await updateAppChat(config, { chatid, addUserList: missing }, fetchImpl);
  }
}

export async function ensureTaskChatForMembers(
  db: DatabaseClient,
  params: { taskId: string; addUserids?: string[] },
  config: WecomConfig,
  fetchImpl: FetchLike = fetch,
): Promise<TaskChatEnsureResult> {
  const taskId = text(params.taskId);
  if (!taskId) return { chatId: null, created: false, reason: "no_task" };
  if (!hasAppCredentials(config)) {
    return { chatId: null, created: false, reason: "no_credentials" };
  }
  const task = await db
    .prepare(
      `SELECT t.id, t.name, t.task_chat_id, t.owner_userid AS task_owner_userid,
              p.owner_userid AS project_owner_userid
       FROM tasks t
       LEFT JOIN projects p ON p.id = t.project_id
       WHERE t.id = ?`,
    )
    .bind(taskId)
    .first<TaskChatRow>();
  if (!task) return { chatId: null, created: false, reason: "no_task" };
  const ownerUserid = text(task.project_owner_userid);
  const taskOwnerUserid = text(task.task_owner_userid);
  if (!ownerUserid && !taskOwnerUserid) {
    return { chatId: null, created: false, reason: "no_owner" };
  }
  const members = [
    ...new Set(
      [
        ownerUserid,
        taskOwnerUserid,
        ...(params.addUserids ?? []).map((id) => text(id)),
      ].filter(Boolean),
    ),
  ];

  let chatId = text(task.task_chat_id);
  let createdNow = false;
  if (!chatId) {
    chatId = taskChatId(taskId);
    const existing = await getAppChat(config, chatId, fetchImpl);
    if (!existing) {
      if (members.length < 2) {
        return { chatId: null, created: false, reason: "not_enough_members" };
      }
      const created = await createAppChat(
        config,
        { name: chatNameForTask(task.name), userlist: members, chatid: chatId },
        fetchImpl,
      );
      chatId = created.chatid;
      createdNow = true;
    }
    await db
      .prepare("UPDATE tasks SET task_chat_id = ? WHERE id = ?")
      .bind(chatId, taskId)
      .run();
  }

  await syncMembers(config, chatId, members, fetchImpl);
  return { chatId, created: createdNow };
}

export type TaskOwnerAssignment = {
  ownerUserid: string;
  partnerId: string;
  chatId: string | null;
  chatCreated: boolean;
  warning?: string;
};

export async function assignTaskOwner(
  db: DatabaseClient,
  params: { taskId: string; ownerUserid: string },
  config: WecomConfig,
  fetchImpl: FetchLike = fetch,
): Promise<TaskOwnerAssignment> {
  const taskId = text(params.taskId);
  const ownerUserid = text(params.ownerUserid).slice(0, 64);
  if (!taskId) throw new Error("缺少 taskId");
  if (!ownerUserid) throw new Error("请填写任务负责人");

  const task = await db
    .prepare(
      "SELECT id, name, brand, quantity, due_at, project_id FROM tasks WHERE id = ?",
    )
    .bind(taskId)
    .first<{
      id: string;
      name: string;
      brand: string;
      quantity: number;
      due_at: string;
      project_id: string;
    }>();
  if (!task) throw new Error("任务不存在");

  await db
    .prepare("UPDATE tasks SET owner_userid = ? WHERE id = ?")
    .bind(ownerUserid, taskId)
    .run();

  const partner = await findOrCreateGroupOwnerPartner(db, ownerUserid);

  const warnings: string[] = [];
  const projectId = text(task.project_id);
  if (projectId) {
    const project = await db
      .prepare(
        "SELECT main_group_member_ids, owner_userid FROM projects WHERE id = ?",
      )
      .bind(projectId)
      .first<{ main_group_member_ids: string; owner_userid: string }>();
    if (project) {
      // 负责人不在成员列表则并入，保持「负责人都在总群」
      const stored = effectiveProjectMembers(project.main_group_member_ids, "");
      if (!stored.includes(ownerUserid)) {
        await db
          .prepare("UPDATE projects SET main_group_member_ids = ? WHERE id = ?")
          .bind(JSON.stringify([...stored, ownerUserid]), projectId)
          .run();
      }
      const mainChat = await ensureProjectMainChat(db, projectId, config, fetchImpl);
      if (mainChat.warning) warnings.push(mainChat.warning);
    }
  }

  let ensure: TaskChatEnsureResult = { chatId: null, created: false };
  try {
    ensure = await ensureTaskChatForMembers(db, { taskId }, config, fetchImpl);
    if (ensure.chatId && ensure.created) {
      await sendTaskChatMessage(
        db,
        taskId,
        taskChatIntroText({
          name: task.name,
          brand: task.brand,
          quantity: task.quantity,
          dueAt: task.due_at,
        }),
        config,
        fetchImpl,
      );
    }
  } catch (error) {
    warnings.push(`任务群创建失败：${error instanceof Error ? error.message : String(error)}`);
  }

  return {
    ownerUserid,
    partnerId: partner.id,
    chatId: ensure.chatId,
    chatCreated: ensure.created,
    warning: warnings.length > 0 ? warnings.join("；") : undefined,
  };
}

export async function sendTaskChatMessage(
  db: DatabaseClient,
  taskId: string,
  message: string,
  config: WecomConfig,
  fetchImpl: FetchLike = fetch,
): Promise<boolean> {
  try {
    const content = text(message);
    if (!content) return false;
    const row = await db
      .prepare("SELECT task_chat_id FROM tasks WHERE id = ?")
      .bind(text(taskId))
      .first<{ task_chat_id: string | null }>();
    const chatId = text(row?.task_chat_id);
    if (!chatId) return false;
    await sendAppChatMessage(config, { chatid: chatId, text: content }, fetchImpl);
    return true;
  } catch (error) {
    console.error(
      `[KOC LOOP] 任务群消息发送失败（task=${taskId}）`,
      error instanceof Error ? error.message : error,
    );
    return false;
  }
}

export function taskClaimBroadcastText(
  taskName: string,
  claimantName: string,
  quantity: number,
) {
  return `【领取】${text(claimantName)} 认领 ${quantity} 份 · ${text(taskName)}`;
}

export function taskChatIntroText(task: {
  name: string;
  brand: string;
  quantity: number;
  dueAt: string;
}) {
  return [
    `【新任务】${text(task.name)}`,
    `品牌：${text(task.brand)}｜数量：${task.quantity} 份｜截止：${text(task.dueAt)}`,
  ].join("\n");
}